Replenish chest

///// First command block

/setblock ~-6 ~ ~ minecraft:lava 0 replace

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// Repeater on 1 tick ////
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///// second CMDB

/setblock ~-4 ~ ~ minecraft:air 0 replace

///// Third CMDB

/setblock ~-3 ~ ~ minecraft:chest 0 replace {Items:[{id:131,Count:1,tag:{display:{Name:"Magical Key",Lore:["Opens Magical Doors"]},ench:[{id:4,lvl:2}]}}]}